<div class="virtual-container" [style.height]="screenHeight+'px'">
  <div [style.height]="listHeight+'px'"></div>
  <div class="virtual-box" [style.transform]="'translateY('+offset+'px)'">
    <div class="virtual-item" *ngFor="let item of showList" [ngStyle]="{height: itemHeight + 'px'}">
      {{item}}
    </div>
  </div>
</div>